Improvement in spirit-levels



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lowing is a full, clear, and exact description thereof, reference being had to the accom `struction and operation.

`L. L. DAVIS, SPRINGFIELD, MASSACHUSETTS.

vLettersuPatent No. 75,533, @lated March 17,- 1868. i

IMPROVEMENT IN SPIRIT-LEVELS. g

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Be it known thatI, L. L. DAVIS, of Springfield, in

` the county' of Hampden, and Commonwealth of Massaf chusetts, have invented a new and useful Improvement in Spirit-Levels and I do hereby declare that the fol- Y panying drawings, making a part of thisV specification, and to the letters of reference marked thereon, in whichv Figure 1 is a side lelevation ot' that portion of a spirit-level to vwhich my invention is applied, and with part of the graduated ring broken away, to show the details of th e adjusting-arrangement.

Figure 2 isaplan view of the same portion of said spirit-level.

The nature of my invention consists in the construction and arrangement of portions of a spirit-level having a revolving bubble-case, whereby the bubble-glass may be put in adjustment with reference to the outer frame or base of the level, without're'moving the bubble-glass from its case; and which construction also obviates the necessity of anyparticular care in irst introducing and securing said bubbleLglass in its saidcasc; and' my said invention may be considered as an improvement upon the invention set forth and des Patent granted to me, September 17,1867, and numbered 68,961.

That others skilled in the art may be able to mak cribedl inA Letters VIn the drawings, a represents the socket or receptacle, into which is inserted and in which revolves or oseillates the `ring D, having therein the bubble-case@ The ring ais perforated' on each side, tions having screw-threads cut therein, and the screws d at into'the said threadedperforations, their points e e protruding beyond the inner surface of the ring a, exactly opposite each other. Into the ring D are placed the studs tz', which may be secured in place by any convenient and proper method,- and so placed that when the ring D is in place inits socket a, the studs z' z' shall be in the same vertical line with the screws or points c e'. The stud z" is bevelled upon that side which is towards the point e', and in such manner tht the bevelled surface ofthe stud z" shall be parallel to the outline of the cone e. The stud z' is set into the ring D, at a distance from the stud z",lequal t'o 'one-fourth of the whole circumference of thc ring D, and is likewise bevelled upon the side towards the point e, having the same bevelled inclination as the outline of the cone e, and they are so arranged that when the bubble-case C is in one position, the stud z" impinges against the cone or point e', audit', the bubble-case C or ring D be turned one-quarter of a revolution," the stud z' impinges against the cone or point e', as shown in redlines. A screw, '0, having a coni-A cal point, is turned linto a threaded perforation in the top of the frame B, its point protruding -beyond the inner surface of the ring a, and the spring c', having aslight indentation at the place where the point of the screw c impnges against it, is placed between the said screws c, and the' ring D,the ends of the said spring resting upon the outer surface of the ring D,. and thus causing more or less pressureto be exerted upon the ring D, as the'screw c is turned in or out.. v I Y The operation of my invention is as follows: If it is found upon-trial that the bnbble-glass is not in perfect adjustment with the base of the frame B', and it should be necessary to depress the side of the bubble-case C, the screw 0l is turned in, and the cone e', in its contact with the bevelled stud i', forces it downwards, which action elevates the other side, F, of the buhblecase C, and the screw d may be correspondingly turned out if desirable. The studs z'z" might be straight'instead of hevclled, as shown, and still be operative, butI prefer them bevelled, as they operate more perfectly, and with a greater degree of nicety.

I-Iaving thus described my invention, what I claim as new, and desire .to secure by Letters Patent, is-

In combination with the screws d d', having the' conical points e e', thc studs z'z", placed in the ring D,

which has a reciprocating rotary motion, all constructed and arranged substantially as herein described and set forth.

g L. L.- DAVIS. Witnesses:

J. P., BUCKLAND,

N. B. SMITH.

havingvthe conicalor tapered points e-e are turned e and use my invention, I will proceed to describe its consaid portare- 

